 

      
    function encode64(input) {  
    	var keyStr = "ABCDEFGHIJKLMNOP" + "QRSTUVWXYZabcdef" + "ghijklmnopqrstuv"  
        + "wxyz0123456789+/" + "=";  
        var output = "";  
        var chr1, chr2, chr3 = "";  
        var enc1, enc2, enc3, enc4 = "";  
        var i = 0;  
        do {  
            chr1 = input.charCodeAt(i++);  
            chr2 = input.charCodeAt(i++);  
            chr3 = input.charCodeAt(i++);  
            enc1 = chr1 >> 2;  
            enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);  
            enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);  
            enc4 = chr3 & 63;  
            if (isNaN(chr2)) {  
                enc3 = enc4 = 64;  
            } else if (isNaN(chr3)) {  
                enc4 = 64;  
            }  
            output = output + keyStr.charAt(enc1) + keyStr.charAt(enc2)  
                    + keyStr.charAt(enc3) + keyStr.charAt(enc4);  
            chr1 = chr2 = chr3 = "";  
            enc1 = enc2 = enc3 = enc4 = "";  
        } while (i < input.length);  
  
        return output;  
    }  